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Bisecting angles |
2001-08-27 |
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From Monica:
Ray QS is the bisector for angle PQR. Find the measure of angle PQS and PQR if the measure of angle SQR is 52 degrees.
Answered by Penny Nom. |
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A sequence |
2001-08-25 |
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From Sharon:
1
11
21
1211
111221
312211
1311221
1113213211
31131211131221
13211311123113112211 What would be the next sequence of numbers? my name is sharon i work in customer service and a friend asked me to solve this.
Answered by Walter Whiteley. |
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Vertices |
2001-08-08 |
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From Jordan:
I am a fifth grader learning geometry with my mom's help, can you please explain what a vertices are??
Answered by Penny Nom. |
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Fourier transform |
2001-08-07 |
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From Adbul:
- Sir, we have the Dirichlet's condition for the Fourier transform : " The function should be integral over the real line " But why we are we neglecting this for example when we take the Fourier transform of an impulse train?
- Suppose we want to travel from one corner of a square of side 'a' to the diagonally opposite corner. We can travel along the sides which gives a pah length of '2a'. We can also do it in steps as shown below:
_ | |_PATH | |_ |_____|
Suppose The step size =DELTA x Then the path length will be again '2a'. Now in the limit DELTA x -->0 again we get '2a' But when we take the limit we get the straight line diagonal whose length is 'SQRT(2)X a' Where did I go wrong?
Answered by Chris Fisher. |
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How far does the fly fly? |
2001-08-07 |
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From Harold:
6 MPH 4 MPH
Rachel ---------------------- Eli
10 Miles apart
The fly is on Rachels handlebars. The fly is scared so it flys back and forth at 20 MP H. How far has the fly flown when Rachel and Eli meet? f
Answered by Penny Nom. |
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Standard angles |
2001-08-05 |
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From Nagaraj:
Why 0o , 30o , 45o , 60o ,and 90o are taken as standard angles in Trigonometry? Why can't we take some other angles as standard angles?
Answered by Chris Fisher. |
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Conformable matrices |
2001-08-05 |
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From Wayne:
Can someone explain the concept of conformable matrices in a way that is easy to understand ? One definition says to multiply matrices rows and columns must conform, ie, 5 x 3 matrix times a 3 x 5 matrix. In the next example, however a 8 x 1 matrix and a 8 x 3 matrix are said to be conformable!
Answered by Steve Kirkland. |
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Linear regression |
2001-08-01 |
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From A student and a mother:
My mom is taking a correspondence course in Simple Linear Regression and Correlation Analysis and we've been arguing about the relationship between the correlation -rxy and standard estimate of error-Sy.x. I took statistics last year in high school and I remember something about the Sy.x being proportionate to the r. Are they inversely related, directly related, not related, or can only range from 0 to 1.00? Her book doesn't say very much and I believe they are inversely related. She says they're directly related.
Answered by Chris Fisher and Penny Nom. |
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Intersection of perpendicular cylindrical surfaces |
2001-07-31 |
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From Charlie:
Please consider two right circular cylinders, perpendicular one to the other, and of unlike radii in a 3 dimensional Cartesian space with mutually perpendicular x,y,z axes. If one cylinder is centered on the y axis with radius ra, and the other on the z axis with radius rb, then the expression for the first surface would be x2 + z2 = ra2, y = any number. Likewise, the second cylinder's surface would be x2 + y2 = rb2, z = any number. It is my intent to define the curve at the intersection of these two cylindrical surfaces. From sketching the conditions it appears that this intersection resembles an ellipse folded about its minor axis.
Answered by Chris Fisher. |
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The radius of a planet |
2001-07-30 |
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From Jessica:
A satellite is orbiting the earth at an altitude of 100 miles. If the angle of depression from the satellite to the horizon is 50 degrees, what is the radius (to the nearest mile) of the planet?
Answered by Harley Weston. |
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1996^1999 and 1999^1996 |
2001-07-29 |
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From Rajesh:
what is greater 19991997 or 19971999?
Answered by Chris Fisher. |
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The best linear model |
2001-07-29 |
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From Rebeca:
I am a student (senior) summer hire working for Dept of the Army Resource Management. I've been assisting the Analyst in developing a model to predict training costs. The technique we used was simple linear regression. Now I've been asked for my opinion in choosing the best model I feel is better. I've chosen #1. Garrison Training but I want a second opinion before I give my choice. I've taken basic statistics last year in high school and will probably be taking more this year. Could you look over the information and give me a reason my choice would not be best? The dep variable-y, is Training costs in dolars per day. | Model | Ind Variable- X | a | b | r | sy.x | | 1. | Garrison Training | 126.31 | 0.982 | 0.9055 | 117.2 | | 2. | Local Training | 212.16 | 1.37 | 0.7937 | 142.7 | | 3. | Man Rig Area | 116.38 | 2.47 | 0.6481 | 175.6 | | 4. | Major Training | 346.12 | 4.67 | 0.7280 | 167.2 |
Answered by Andrei Volodin. |
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e^pi > pi^e |
2001-07-27 |
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From Dusty:
What book(s) contain a proof that ePi > Pie? I think it might be in Problems in Analysis published by Springer-Verlag but I have not been able to check.
Answered by Chris Fisher. |
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A trig identity |
2001-07-27 |
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From Jeff:
prove this identity and show steps
tan(x/2+pi/4)=secx+tanx
Answered by Harley Weston. |
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Radian measure |
2001-07-26 |
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From Amy:
i have to find out what is meant by the radian measure of an angle and compare it to the measure of an angle in degrees.
Answered by Harley Weston. |
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